Rubicon - Slip Yoke or Fixed

[BellValleyAT]

Does the JL Rubicon TCase have a slip yoke rear output or fixed?

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[Zandcwhite]

Fixed

 

[BellValleyAT]

Fixed

Thanks!

Is there a rule of thumb for lift kit size before a new, longer driveshaft (or with double-cardan) is required?

Sorry, new to JLs. Thanks!

 

[grimmjeeper]

They use Rzeppa joints in the JL at the transfer case and rear axle. The front axle has a single U-joint. Rzeppas are CV joints. Though they can't tolerate as much angle as a double cardan joint. And they're weaker than they should be. So upgrading to U-joints is a good idea if you go over 2-3" of lift. Lots of places sell upgrade kits.

 

[Zandcwhite]

The rear is good at any reasonable lift height. The front runs into issues on droop. Shocks over 29" extended length are problematic.

 

[grimmjeeper]

The rear is good at any reasonable lift height. The front runs into issues on droop. Shocks over 29" extended length are problematic.

2 door does tend to bind at lower lift heights than a 4 door. The rear driveshaft is so much shorter on the 2dr.

 

[BellValleyAT]

They use Rzeppa joints in the JL at the transfer case and rear axle. The front axle has a single U-joint. Rzeppas are CV joints. Though they can't tolerate as much angle as a double cardan joint. And they're weaker than they should be. So upgrading to U-joints is a good idea if you go over 2-3" of lift. Lots of places sell upgrade kits.

Appreciate it!

 

[Zandcwhite]

2 door does tend to bind at lower lift heights than a 4 door. The rear driveshaft is so much shorter on the 2dr.

But where is that cutoff? I've wheeled with several 3" lifted JLs on stock shafts. Which is why I said reasonable lift heights. You don't see too many 4"+ lifted JLs and they'd look silly if they weren't on 40"+ tires. At that point you're probably into 60s and the stock shafts are long gone anyway. I know for a fact on the JLUR that the stock shaft is fine on 31" extended length shocks at full droop in the rear.

 

[grimmjeeper]

But where is that cutoff? I've wheeled with several 3" lifted JLs on stock shafts. Which is why I said reasonable lift heights. You don't see too many 4"+ lifted JLs and they'd look silly if they weren't on 40"+ tires. At that point you're probably into 60s and the stock shafts are long gone anyway. I know for a fact on the JLUR that the stock shaft is fine on 31" extended length shocks at full droop in the rear.

4 doors can flex a lot more than the 2 doors without binding. The axle moves just as much but with the longer driveshaft the angles never get too far.

Most 4 doors don't push the angle too far.

And it's not so much the lift height as the droop distance, especially on the front axle. And there's way too many variables in that equation. Shock travel, whether you outboard the lower shock mount to eliminate binding, the joints in your control arms, etc.

 

[Zandcwhite]

4 doors can flex a lot more than the 2 doors without binding. The axle moves just as much but with the longer driveshaft the angles never get too far.

Most 4 doors don't push the angle too far.

And it's not so much the lift height as the droop distance, especially on the front axle. And there's way too many variables in that equation. Shock travel, whether you outboard the lower shock mount to eliminate binding, the joints in your control arms, etc.

I agree, but 2dr or 4dr the front is the same. Obviously the rear on a 2dr will bind before the 4dr, but I haven't seen it as an issue with any "normal" builds. Most 2dr guys won't go past 37s and 3" and at that point it didn't seem to be an issue.

 

[grimmjeeper]

I agree, but 2dr or 4dr the front is the same. Obviously the rear on a 2dr will bind before the 4dr, but I haven't seen it as an issue with any "normal" builds. Most 2dr guys won't go past 37s and 3" and at that point it didn't seem to be an issue.

Yes. Fronts are virtually the same 2dr to 4dr.


I added the metalcloak shock relocation kit and longer travel shocks on mine. 2.5" lift with Clayton arms and 37s. My front Rzeppa showed signs of being over extended when I swapped out for a Tom Woods front driveshaft.

 

[grimmjeeper]

Here's the video we did on my front driveshaft swap. I show the Rzeppa next to the double cardan joint in here.

 

[Nokones]

I went with the Tom Woods 1350 drive shafts and the rear is a Double Cardan. You need to make sure that the rear driveshaft angle is no more than two degrees different than the Pinion Angle to eliminate any low speed harmonics.

Adjustable control arms and Track Bar mostly likely may come into play in order to adjust your angle.

 

[Terrymo]

Here's the video we did on my front driveshaft swap. I show the Rzeppa next to the double cardan joint in here.

I see some people putting RTV on the splines of the yoke, and some people putting it on the contact surface of the nut. Pros and cons of each? Why not both?
Also I see some people only using blue loctite and some using red. Opinions? Thanks

 

[Terrymo]

@grimmjeeper regarding my previous post, looking at Tom Woods instructions I see they suggest RTV on the splines as well.

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